The Best Type of Cactus for a Desk

A small, desert cactus is perfect for an office desk.

Your desk is probably like most office spaces, with warm and dry air, fluorescent light fixtures and subject to random drafts from the door, air conditioning or heating ducts. Add infrequent watering, weekends and vacations when no one is available to care for your plants and your desk becomes a desert wasteland. Of the more than 1,000 species of cactus, some grow in jungles but the majority grow in deserts. While most houseplants aren't suited for an office desk, most cacti thrive in the adverse conditions of an office environment.

Small Cactus Species

The best cactus for an office is one that thrives with little water and plenty of light -- and is small enough to fit on a desk. Cacti range in size from the giants of the Sonoran Desert to the Chihuahuan Desert's living rock cactus (Ariocarpus fissuratus), which only grows 3 to 5 inches in diameter. Other small cacti suited to office life include the sea urchin cactus (Astrophytum asterias) at only 2 inches tall by 4 inches wide, bishop's cap (Astrophytum myriostigma) at 10 inches tall by 6 inches wide and Mammillaria zeilmanniana at 5 inches tall by 3 inches wide. All of these cacti thrive outdoors in U.S. Department of Agriculture plant hardiness zones 9a through 11.

Indoor Cactus Care

Caring for an indoor cactus is relatively easy. Water the plant every two to three weeks -- whenever the soil is dry -- and give it plenty of light. Cacti thrive in full sun; simply add a lamp with a fluorescent bulb to your desk. A lamp timer ensures that your cactus receives the additional light even when the office is closed. Fertilize the cactus once a month with a 5-10-5 fertilizer, mixing 1 teaspoon fertilizer with 1 gallon of water. The most difficult part of growing a cactus on your desk is convincing your coworkers that they don't need to water your cactus for you when you're on vacation. Overwatering is the usual cause of a cactus' early death.

Tropical Cactus Varieties

While you may think of spiny, desert plants when you consider a cactus for your desk, there are several tropical cacti that thrive indoors. The familiar Christmas (Schlumbergera bridgesii), Thanksgiving (Schlumbergera truncata) and Easter cacti (Rhipsalidopsis gaertneri) are all varieties of tropical cacti that thrive in USDA zones 10 through 11. Water your plant in the sink when the soil is dry to a depth of 3 to 4 inches, allowing the excess water to drain from the flowerpot before returning it to your desk. Place the flowerpot on a tray filled with pebbles and water to provide extra humidity for these tropical cacti. These jungle cacti do much better in medium light and should only be placed in direct sunlight in the winter.

Succulents -- Cactus-Like Plants

While all cacti are succulents, the reverse isn't true. Not all succulents are cacti, even if they appear cactus-like. Among the succulents often grown on office desks are are jade plants (Crassula argentea) and aloes (Aloe spp.), which thrive in USDA zones 10 through 11 and 9 through 11. Another succulent that is normally grown outside is a hens and chicks (Sempervivum tectorum), also known as the house leek. While it requires full sun, a hens and chicks plant thrives in USDA zones 3 through 8, making it a good choice for a windowsill or sunny desktop in a drafty, cold, warehouse office.